Changing Fast Carbs to Slow Carbs for Weight Loss | Jason Fung

hi today I'm going to talk about the five types of resistant starch and how they might help you to try to lose weight and it's coming right [Music] up starches things like oat and beans and wheat and rice are called polysaccharides and that means that they're long chains of glucose which is a type of sugar and they come arranged in two main forms one called Amal optin which is about 70% in the human diet and the other type is amalo which is about 30% the starches are usually classified into three different types rapidly digested starch

which means that the glucose is released within about 20 minutes of eating then there's slowly digested starch which is slower than 20 minutes and then resistant starch which is not broken down at all and this replaces the old classification of carbohydrates which was complex versus simple carbohydrates and the old classification was based on how long those chains of glucose were if it was a simple carbohydrate it was one or two molecules and it was thought that that would lead to a very quick rise in glucose and a complex carbohydrate which is longer chains like the

amalo and Amal optin were thought to be digested slower but it turns out not to be true because many many of these uh long chains that is complex carbohydrates actually are rapidly digested and therefore cause a very quick Spike so that old classification wasn't useful because it's really based on a chemical composition of the starge and is not based on the human physiologic response which is why we use these different terms tin has a different structure than amalo so Amal optin is more water soluble and makes it easier to be degraded by enzymes called amasis

the uh Amal optin comes in three different types Amal optin a which is found in wheat and is the most easily digested Amal optin C is the hardest to digest and those are found in things like beans Amal opcin B which is found in potatoes and bananas is sort of intermediate between the two amalo with its helical structure which is straight is much harder to digest and therefore leads to a much slower rise in the glucose and the insulin and in this study for example you see that this is true in both normal um people

and also hyperinsulinemic people if they eat more amalo compared to Amal optin the amount of insulin that is released is much less even though the amount of carbohydrate is the same and as we've seen the speed of the digestion is critically important to how much gluc glucose and Insulin released there's actually six major forms of uh ways that can be influence the uh the carbohydrate from uh what you eat to how quick the glucose Rises so the first is as we've discussed the amalo uh pectin to amose ratio and how much resistance starch there is

uh second is the particle size that is if you have much larger particles they tend to be digested much slower if you have something which is grind up and very small it can be digested very quickly so uh for example if you have uh deel cut oats versus very finely milled instant oats there's a difference because the particle size is smaller the third is a cell wall Integrity so if you have the uh carbohydrate within an intact cell wall it can't be digested that's why fiber is often considered an indigestible carbohydrate if you break down

that cell wall by taking wheat for example and grinding it very very fine into a dust it gives it uh a lot of opportunity for the amasis those enzymes in our body to break it down leading to an extremely rapid rise in blood glucose compared this finely machine grade uh industrially processed wheat to say stone ground wheat and you find that the the cell wall Integrity is more intact and therefore a slower rise number four is if you eat the fats and proteins along with the carbohydrates and I did a whole YouTube video uh describing

why food order matters and why eating the carbs last might be more beneficial uh number five is the presence of acidic Foods things such as vinegar and other uh fermented foods can influence the speed at which is digested by influencing the amount of amasis and again I did a whole YouTube video on that if you want to check that out and number six is something called phenolic which we may address in another video when phenolics are antioxidants they're phytochemicals so they're found uh from plants and they're things called like phenolic acid and flavonoids and lignins

and they modulate carbohydrate digestion and glucose absorption by also inhibiting inhibiting these Amal phes that break down the carbohydrate and um they can also influence the intestinal glucose transporter so by by inhibiting the amalay is it makes the absorption much slower and certain Studies have shown that uh perhaps the most important factors could be the amount of uh fiber and also the uh presence of uh phenolics so what about resistant starch because resistant starch is not digested at all and by taking more resistant starch you might be able to influence that how much carbohydrate you

can take and reduce it and there's five different types of resistant starch because they don't get digested at all it goes to the colon and the carbohydrate then gets acted on by the uh gut microbiome so those bacteria that are in the colon start to break it down into things such as short chain fatty acid or SF s CFA and that is important because that has other influences it stimulates for example glp1 which is a hormone which uh May promote satiety and decrease gastric emptying and also peptide YY which promotes satiety so this fiber even

though there is no um absorption the carbohydrate goes straight through us doesn't going absorb can still make us feel more full and make us want to stop eating and this will have an influence in terms of glucose sensitivity and decreasing the amount of insulin released the the the first type of resistant starch is type one resistant starch which is that the carbohydrate is trapped within a physical barrier um or a uh and that usually is an intact cell wall because it is contained with in that cell wall or perhaps a protein matrix therefore the digestive

enzyme s like the amales can't get add it because they're physically blocked the fiber is the most classic example of that where the carbohydrate is trapped within the intact cell wall and therefore you can't do it you can release the carbohydrate by industrial processes such as grinding but also Milling sometimes chewing can also uh release that um so if you uh look at those examples like uh machine ground Flow versus uh stone ground flour or Steel oats versus instant oats there's clearly a difference when it comes to the effect on our bodies even though the

carbohydrate is the same the second type of starch is called high amalo starch and because the amalo is digested slower you can modify mostly genetically the uh corn and sometimes wheat to have a much higher amalo concentration it's called hm or high amalo maze um that's not very common however uh the other way to look at it is to look at the different varieties and here they've done some um some studies on rice and certain types of rice are much higher in amalo than others the highest variety rice is basmati rice as well as Jasmine

and they're about 30% so on par with wheat but the uh sticky rice or glutenous rice has almost 0% amalo it's mostly almost all amalo pectin and in between is a short grain rice which is about 10 to 20% the other thing that is very high in amalo are unripened potatoes unripened bananas Maybe Baby potatoes as well um there the starches are very uh difficult to digest the third type of resistant starch or type three resistant starch is uh cooking and then cooling starches and this is very interesting because heating the starches actually causes gelatinization

which is turning it into a more liquid form so cold rice for example is very crunchy because it's it's a crystal and then as it's more liquid it's smoother and softer and much easier to eat as that Rice cools uh it forms a new crystal structure in a process called retrogradation so you may also see that term retrograded starch and this makes the starch more stable and again less susceptible to amalay and again if you uh the amalay can't break down the starch it can't get absorbed so therefore the rise in glucose is much slower

than if you had just regular rice so cooked and then cooled rice uh can be compared in this study for example uh they they found that there was a small but significant uh decrease in the rise in glucose when you had uh type 3 resistant starch potatoes on the other hand if you were to cook them cool them and then reheat them uh most of that starch just goes back into its normal structure so it doesn't have any effect but the good thing about potatoes is that you can eat them cold so if you cook

them and then cool them and then eat them cold such as with potato salad for example then again you can take advantage of this resistant starch so uh one study for example showed that if you ate uh potato salad where you also had some vinegar dressing which may play an effect you could actually reduce the gemic index by a whopping 41% compared to regular potatoes and uh reduce the insulin by 31% so that's a very interesting way to modify uh the starch which is called retrogradation or type 3 resistance starch type four is a chemically

modified starch and this is not recommended because it's highly processed what they do is they use uh chemicals to do things like crosslinking etherization esterification and just by hearing the name you know that that's probably not something you want to eat and type five is the complex of the starch and lipid where the fat acts as a physical barrier separating uh the amalay and the starch and therefore preventing the quick breakdown so uh this has not been studied well so there's not a lot of evidence however there is a small study for example where they

looked at stir fried rice and oil versus fried rice without oil and the oil acts as a physical barrier to make it uh easier to uh have so those are the different types of resistant starch there's five different types and it's very important that all starches are not the same there's those six different ways that you can modify it so again it's not the carbohydrate necessarily because all of these have the same amount of carbohydrate but what you what what you do to the carbohydrate whether you change it into a more resistant form or you

add things like proteins or fats or vinegars or you uh keep it in a more whole form uh that that can really influence the amount of uh the how quickly the the uh glucose Rises and therefore the amount of insulin produced and it's that hormone insulin which is driving weight gain I hope you've learned something I'll see you next week